Cooling system diagnostic method

Patent metadata

Field	Value
Publication number	US-9790842-B2
Application number	US-201514617609-A
Country	US
Kind code	B2
Filing date	Feb 9, 2015
Priority date	Feb 9, 2015
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A method for operating an engine cooling system is provided. The method includes monitoring a coolant temperature profile after engine shut-down and indicating a low coolant level based on the coolant temperature profile determined after engine shut-down.

First claim

The invention claimed is:

1. A method for operating an engine cooling system comprising:
after an engine shut-down, sending power to a controller;
at the controller, receiving a temperature signal from an engine temperature sensor and determining a coolant temperature profile based on the temperature signal; and
adjusting engine power output during a subsequent engine start-up based on the coolant temperature profile determined after engine shut-down.

2. The method of claim 1 , wherein adjusting engine power output during the subsequent engine start-up comprises one or more of reducing engine power output during the subsequent start-up, inhibiting engine operation until coolant temperature is above a threshold, limiting boost provided to the engine by a compressor during the subsequent start-up, decreasing airflow to the engine during the subsequent start-up, limiting engine fuel injection, and inhibiting of spark retard during the subsequent start-up.

3. The method of claim 1 , further comprising discontinuing power transfer to the controller before sending power to the controller and determining the coolant temperature profile.

4. The method of claim 1 , wherein the determination of the coolant temperature profile is also based on environmental conditions.

5. The method of claim 1 , where the coolant temperature profile is compared to a predicted coolant temperature profile to determine whether a coolant level is lower than a threshold.

6. The method of claim 5 , where the predicted coolant temperature profile is generated based on an exponential decay.

7. The method of claim 1 , further comprising, at the controller, during engine combustion operation, determining a coolant level based on the temperature signal from the temperature sensor in the engine.

8. The method of claim 1 , where determining the coolant temperature profile is initiated in response to a climate control unit generating heat less than a threshold value.

9. The method of claim 1 , further comprising, triggering a low coolant level indicator in a cabin of a vehicle based on the coolant temperature profile determined after engine shut-down.

10. The method of claim 9 , further comprising increasing an output of a heat exchanger fan during the subsequent engine start-up in response to triggering of the low coolant level indicator.

11. An engine cooling system comprising:
a cooling circuit circulating coolant through passages traversing an engine;
a heat exchanger coupled to the cooling circuit;
a temperature sensor coupled to at least one of the cooling circuit and the engine; and
a controller configured to:
after engine shut-down, receive power;
determine a coolant temperature profile based on a signal sent from the temperature sensor; and
adjust engine power output during a subsequent start-up based on the coolant temperature profile determined after engine shut-down.

12. The engine cooling system of claim 11 , where the coolant temperature profile is compared to a predicted coolant temperature profile to determine how to adjust engine power during the subsequent start-up.

13. The engine cooling system of claim 12 , where the predicted coolant temperature profile is included in a set of predicted coolant temperature profiles that are predicted and stored in memory in the controller.

14. The engine cooling system of claim 11 , where the controller is configured to receive power after engine shut-down and determine the coolant temperature profile in response to one of an engine shut-down event and a cabin heat exchanger coupled to the cooling circuit generating heat less than a threshold value.

15. A method for operating an engine cooling system comprising:
after engine shut-down and vehicle off condition, maintaining power to a controller that determines a coolant temperature profile over time;
comparing the coolant temperature profile to a predicted coolant temperature profile; and
if a deviation between the determined coolant temperature profile and the predicted coolant temperature profile exceeds a threshold value, triggering a low coolant level indicator in a vehicle cabin based on the coolant temperature profile determined after engine shut-down.

16. The method of claim 15 , where comparing the coolant temperature profile to the predicted coolant temperature profile includes determining differences between a plurality of coolant temperatures in each profile and summing the temperature differences to determine if the profile deviation is greater than the threshold value.

17. The method of claim 15 , where the coolant temperature profile is determined in direct response to an engine shut-down event and comparing the coolant temperature profile to the predicted coolant temperature profile is implemented during engine shut-down.

18. The method of claim 15 , further comprising after engine shut-down and before determining the coolant temperature profile, sending power to the controller and inhibiting power transfer to the controller after triggering the low coolant level indicator.

Assignees

• Ford Global Tech Llc

Inventors

• Dudar Aed M
• Jentz Robert Roy

Classifications

• B60H1/00

  Heating, cooling or ventilating devices · CPC title

• F01P2031/18

  Detecting fluid leaks · CPC title

• F01P11/16 Primary

  concerning coolant temperature (F01P11/20 takes precedence) · CPC title

• F01P11/18 Primary

  concerning coolant pressure, coolant flow, or liquid-coolant level · CPC title

• F01P2050/22

  Motor-cars · CPC title